CNN
As CNN reported, at least four ships that washed up on the shores of Japan this week have skeletons on board.

The scene sounds like a scary movie or spooky Halloween story.

At least four boats that washed up on the shores of Japan this week have human skeletons on board, CNN reported. Authorities haven’t confirmed the boats’ origins, but suggested they might be from North Korea.

One wooden boat, which washed up on the Miyazawa beach on the island Honshu, had eight skeletons in the hull of the vessel.

Officials couldn’t confirm if the boats came from North Korea. But the design and debris matched previous North Korean boats that washed up before.

Satoru Miyamoto, a professor at Seigakuin University and an expert on North Korea, told CNN that Japan has seen an increase in boats washing up on shore since 2013.

"It's after Kim Jong Un decided to expand the fisheries industry as a way of increasing revenue for the military. They are using old boats manned by the military, by people who have no knowledge about fishing," Miyamoto said. "It will continue."

Japan and North Korea have been linked in the news this week because of missile test predictions. According to Reuters, Japan detected a radio signal that suggests North Korea is preparing another ballistic missile test.

A Japan government source told Reuters such signals aren’t unusual. No fresh activity has been noted, either.

Still, the signals have put Japan on alert for any possible missile launch.

North Korea’s missile launch tests come despite warnings from the U.N. Security Council, which approved sanctions against the country in response to missile testing.

The country said recently it plans to build a missile that would strike the U.S. mainland, according to USA Today.

"North Korea has been developing its nuclear weapons at a faster-than-expected pace," said Cho Myoung Gyon, South Korea's unification minister, according to USA Today.